Spray cleaning system

ABSTRACT

A spray cleaning head is mounted on a reciprocating cleaning fluid supply tube extending from the open end of a hydraulic cylinder. An annular piston on the tube, the tube itself, and the cylinder define an expansible chamber within the cylinder. A pump supplies cleaning fluid to the closed end of the hydraulic cylinder, whereby the cleaning fluid exerts pressure on the annular piston, and means are provided for supplying fluid to and draining fluid from the expansible chamber. The pressure exerted by the cleaning fluid on the annular piston moves the supply tube and the cleaning head from a retracted to an extended position when fluid is drained from the expansible chamber, and the supply tube and cleaning head are moved back to the retracted position when fluid is supplied to the expansible chamber. In some embodiments, reciprocating the supply tube moves the cleaning head into and out of an open ended casing attached to the hydraulic cylinder and surrounding the supply tube. A lid closes the end of the casing when the cleaning head is in the casing; and means are provided for filling the casing with fluid when the lid is closed, thereby protecting the cleaning head. Where the cleaning head is of the type having a rotating housing and nozzles rotatably attached to the housing, the lid is preferably attached to the rotating housing, and means are provided for pivoting the lid to close the open end of the casing as the cleaning head moves into the casing and for pivoting the lid out of the spray pattern of the nozzles as the cleaning head moves out of the casing.

United States Patent 1 Nunlist et al.

[451 Feb. 12,1974

[ 1 SPRAY CLEANING SYSTEM [75] Inventors: Erwin J Nunlist, Penfield; Howard G. Coleman, Naples, both of NY.

[73] Assignee: Sybron Corporation, Rochester,

[22] Filed: Mar. 9, 1973 [21 Appl. N0.: 339,836

[52] US. Cl 239/227, 239/261, 239/265, 230/288.3, 134/167 R [51] Int. Cl B05b 3/06, B05b l/28, B08b 3/02 [58] Field of Search... 239/225, 227, 240, 241, 243, 239/247, 251, 261, 263, 265, 288, 288.3,

288.5, 264; 134/167 R, 168 R, 167 C, 168 C Primary ExaminerR0bert S. Ward, Jr. Attorney, Agent, or Firm--Theodore B. Roessel [57] ABSTRACT A spray cleaning head is mounted on a reciprocating INLET DRAIN cleaning fluid supply tube extending from the open end of a hydraulic cylinder. An annular piston on the tube, the tube itself, and the cylinder define an expansible chamber within the cylinder. A pump supplies cleaning fluid to the closed end of the hydraulic cylinder, whereby the cleaning fluid exerts pressure on the annular piston, and means are provided for supplying fluid to and draining fluid from the expansible chamber. The pressure exerted by the cleaning fluid on the annular piston moves the supply tube and the cleaning head from a retracted to an extended position when fluid is drained from the expansible chamber, and the supply tube and cleaning head, are moved back to the retracted position when fluid is supplied to the expansible chamber.

In some embodiments, reciprocating the supply tube moves the cleaning head into and out of an open ended casing attached to the hydraulic cylinder and surrounding the supply tube. A lid closes the end of the casing when the cleaning head is in the casing; and means are provided for filling the casing with fluid when the lid isclosed, thereby protecting the cleaning head. Where the cleaning head is of the type having a rotating housing and nozzles rotatably attached to the housing, the lid is preferably attached to the rotating housing, and means are provided for pivoting the lid to close the open end of the casing as the cleaning head moves into the casing and for pivoting the lid out of the spray pattern of the nozzles as the cleaning head moves out of the casing.

23 Claims, 4 Drawing Figures PATENTED FEB 1 2 I974 SHEET 1 OF 3 INLET PATENTEU FEB 1 2 I974 SHEEI 2 (IF 3 SPRAY CLEANING SYSTEM BACKGROUND OF THE INVENTION This invention relates to cleaning apparatus, and more particularly to an improved spray cleaning system for vessels such as chemical reactors, storage tanks and the like.

The chemical, food, and beverage processing industries use various processing and storage vessels that 'must be cleaned frequently. For example, batch polymerizers usually must be cleaned after each batch. Typical prior art spray cleaning systems for cleaning vessels of this sort are disclosed in U.S. Pat. Nos. 3,444,869 Guignon, 3,599,871 Ruppel and 3,645,452 Stoeckel. While these systems offer advantages over older techniques for cleaning these vessels, such as hand scraping, spraying with a hand lance, and flushing with solvent, they still present certain drawbacks.

Stoeckel and Ruppel disclose portable systems that are inserted into the vessel during the cleaning cycle and then removed. This adds steps to the operation of the systems and necessitates pulling a vacuum on and purging the vessel with an inert gas one or more times after the cleaning system is removed in order to remove air. Furthermore, in certain cases it may be desirable to clean a portion of the vessel, such as the head, while the vessel is pressurized, as for example during a processing cycle. The Stoeckel and Ruppel systems cannot be used for this type of cleaning in most cases.

Gui'gnons system, which is permanently mounted in the vessel, eliminates the purging and handling problems inherent in Stoekel and Ruppel, and also provides a system which can be utilized during a processing cycle. However, Guignons system for moving the cleaning head within the vessel is somewhat complicated. Furthermore, since no provisions are made for protecting the spray head from chemicals being processed or stored in the vessel, Guignons spray head is subject to fouling, product build-up, and/or corrosion.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved system for cleaning vessels.

Another object of this invention is to provide a simpler system forpositioning and supplying cleaning fluid to a spray cleaning head within a vessel. The system includes a hydraulic cylinder having an open end and a closed end. A cleaning :fluid supply tube extends through the open end of the cylinder and is adapted for reciprocation within the cylinder. The cleaning head is supported by and reciprocates with the supply tube. The cylinder, the supply tube and an annular piston on the supply tube define an expansible chamber within the cylinder. A pump supplies cleaning fluid to the closed end of the cylinder, whereby the'cleaning fluid exerts pressure on the annular piston, and means are provided for supplying fluid to and draining fluid from the expansible chamber. The pressure exerted by the cleaning fluid on the annular piston moves the supply tube and the cleaning head from a retracted to an extended position when fluid is drained from the expansible chamber, and the supply tube and cleaning head are moved back to the retracted position when fluid is supplied to the expansible chamber. Thus, the cleaning fluid supplied by the pump also serves as a means for positioning the cleaning head at the desired location within the vessel. 4

Yet another object of this invention is to provide means for protecting the spray head when it is not in use. According to the invention, the reciprocating supply tube is surrounded by an open ended casing. Reciprocating the tube moves the cleaning head into and out of the casing. A lid closes the end of the casing when the cleaning head is inside, whereby the cleaning head is protected from materials within the vessel. Preferably, in order to maximize the isolation of the cleaning head, means are provided for filling the casing with fluid when the lid is closed.

A still further object of the invention is to provide an enclosure for a spray cleaning head mounted on a reciprocating cleaning fluidv supply tube,'and having a housing adapted for rotation about the supply tubes longitudinal axis and nozzles rotatably attached to the housing. An open ended casing surrounds the reciprocating supply tube, whereby reciprocating the supply tube moves the cleaning head into and out of the casing. A lid is attached to the rotating housing. The lid pivots out of the spray pattern of the nozzles as the cleaning head moves out of the casing, and pivots to close the open end of the casing as the cleaning head moves into the casing.

Other objects and advantages of this invention will be apparent from the following description.

DRAWINGS FIGS. 1, 2 and 4 are partially sectioned, partially diagrammatic views of three embodiments of this invention.

FIG. 3 is a cross-sectional view taken along lines 33 of FIG. 2.

DETAILED DESCRIPTION FIG. 1 illustrates a system suitable for use in relatively small openings in existing vessels. Typically, this system only requires about a three inch opening in the vessel wall, whereas the systems shown in FIGS. 2 and 4 require approximately fourteen and six inch openings respectively.

In FIG. 1, a hydraulic cylinder 10 with an open end 11 and a closed end 12 is mounted on a nozzle 13 such as is typically used on glass linked vessels for connecting feedlines and installing baffles, clip pipes and the like. A cleaning fluid supply tube 15 extends through the open end 11 of the cylinder, through the nozzle 13 and into the vessel. A spray cleaning head, generally referred to as 16, is attached to and reciprocates with the tube. A variety of commercially available spray heads may be'used in this invention, however, heads such as the one shown in U.S. Pat. No. 3,637,138 to J. H. Rucker are preferred because this type of unit provides a concentrated, forceful spray that removes adhered material from the walls of the vessel. Units such as these have a first rotating housing 17 that rotates about the longitudinal axis of the supply tube, a nozzle housing 18 attached to the first housing and adapted for rotation about an axis normal to the supply tubes axis, and a plurality of nozzles 19 attached to the nozzle housing. Typically, the nozzles are offset so that the reactive force of the liquid discharged from the nozzles helps rotate the housings. In some units of this type, this reactive force assists a turbine (not shown) driven by the cleaning fluid and connected to the first rotating housing 16 by a gear train.

The cleaning fluid is supplied by a pump 30, typically a centrifugal pump with a capacity of 200 to 300 gpm at a discharge pressure of 200 to 300 psi, which is connected to the closed end 12 of the hydraulic cylinder by a throttling-valve 31 and a check valve 32. In most cases, water will provide satisfactory cleaning with this system, however, various other cleaning fluids may be used if desired.

The cleaning fluid is also used to position the cleaning head within the vessel. An annular piston 22 is mounted on or made integrally with the supply tube 15, and the cleaning fluid entering the closed end of the cylinder bears against this piston, thereby urging the cleaning head towards the center of the vessel. The piston 22, supply tube and cylinder 10 also define an expansible chamber 23 within the cylinder. Seals 24, 25 are provided at the open end 11 of the cylinder and on the annular piston 22 to prevent leakage of fluid from or into this chamber. The chamber 23 is connected to the supply pump 30 by a three-way valve 35. At the end of each cleaning cycle, the valve 35 is turned to the position shown in FIG. 1, and the throttling valve 31 is partially closed. As a result, cleaning fluid passes into the expansible chamber 23, forcing the piston 22 upward and retracting the cleaning head 16 toward the cylinder. A needle valve 36 is provided in the line to the expansible chamber 23 in order to control the rate of movement of the piston in the cylinder.

At the beginning of the next cleaning cycle, the three-way valve 35 is turned to connect the expansible chamber 23 to a drain line 37, thereby allowing fluid to escape from the expansible chamber. At the same time, the supply pump 30 is started and the throttling valve 31 is opened to exert the full pressure of the pump on the piston 22, thereby moving the cleaning head into the extended position.

Positioning of the cleaning head is achieved simply and without opening the vessel. Furthermore, this system can be used with the vessel pressurized, and with the cleaning head either fully extended into the vessel, partially extended, or in the retracted position shown in the drawing. Operation with the cleaning head retracted or only partially extended may be desirable in certain cases in order to clean specific parts of the vessel. For example, in batch polymerization it may be desirable to operate the system with the head retracted in order to prevent build up of polymer in the head space at the top of the vessel. If desired, various indicators can be added to the hydraulic cylinder so that the oper-. ator can readily determine the position of the piston and of the cleaning head.

FIG. 2 illustrates another embodiment of this invention, which offers the same simplicity and flexibility of operation as the system shown in FIG. 1, and also provides protection for the cleaning head. In this system, an open ended cylindrical casing 70 is attached to the hydraulic cylinder 40 and extends coaxial to and surrounding the cleaning fluid supply tube 45. Reciprocating the supply tube 45 moves the cleaning head 46 into and out of the casing 70. A lid 71, attached to the rotating housing 47, seats against a lip 72 on the open end of the casing and closes the end of the casing when the cleaning head is in the casing. When the lid is closed, the casing can be filled with fluid in order to protect the head from the materials in the vessel and thereby minimize corrosion and/or fouling of the head.

As in FIG. 1, the cleaning fluid is supplied by a centrifugal pump connected, by a shut-off valve 61 and a check valve 62, to the closed end 42 of the hydraulic cylinder. However, in FIG. 2, fluid is supplied to the expansible chamber 53 by a second pump 63, which is connected to the expansible chamber by a three-way valve 65. Pump 63 is also connected by a pressure relief valve 68 to the closed end 42 of the hydraulic cylinder. The second pump 63 has a much smaller capacity and a higher discharge pressure than the main supply pump 60. Whereas the main supply pump is typically a centrifugal pump with a capacity of 250 gpm at a pressure of 250 psi, the second pump 63 may be a small positive displacement pump having a capacity of around .1 gallon per minute. Since this pump supplies fluid to the expansible chamber 53 at a low rate, there is no need for a flow control valve in the line to the chamber. However, a needle valve 66 is provided in the drain line 67 in order to control the rate at which the cleaning head is moved into the extended position.

The cleaning head is retracted by turning the threeway valve to the position shown in FIG. 2. When the cleaning head is fully retracted, the fluid from pump 63 passes through the pressure relief valve 68 and fills the casing 70 with fluid. Pump 63 may be allowed to continue to run, thus supplying a slow flow of liquid to the casing 70 in order to make up for any leakage between the lid 71 and the casing.

As is shown in phantom in FIG. 2, the lid 71 is adapted to pivot out of the spray pattern of the nozzle as the cleaning head moves out of the casing, and to pivot back again to close the end of the casing as the cleaning head moves back inside. As is best seen in FIG. 3, the lid 71 is pivotally attached to pins 73 extending from a frame 74 attached to the rotating housing 47 of the cleaning head 46. Thus, the lid rotates with the housing. The pivot pins 73 are located on the opposite side of the rotating housing 47 from the nozzles 49, which allows the lid to 'pivot out of the nozzles spray pattern. The pivot pins are also offset from the center of gravity of the lid. Thus, as the cleaning head moves out of the casing, the weight of the lid pivots it down and out of the spray pattern. If desired, counterweights may be added to the lid to insure that the lid pivots completely out of the spray pattern.

Since the weight of the lid is used to open it, this sys tem can only be utilized where the unit is installed with the supply tubes axis generally in a vertical position. It is believed that this system will operate satisfactorily if the supply tubes axis is within about 30 of vertical. If the system is installed in some other position, various modifications can 'be made. For example, torsion springs'may be utilized to pivot the lid.

In the system shown in FIGS.- 2 and 3, the lid is closed by a curved member 75 extending from one side of the lid 71. As may be seen in the phantom view in FIG. 2, when the lid is in the open position, the curved member 75 extends at least as far from the supply tubes axis as the lip 72 of the casing, which is generally coaxial with the supply tube 45. As the cleaning head is retracted into the casing, the curved member pivots the lid 71 so that it seats squarely against the lip. The lip is located in a plane at right angles to the supply tubes axis, and the lid pivots about an axis parallel to the plane of the lip. Thus, the lid seats squarely against the lip regardless of the rotational position of housing 47. Shims 76 are provided at the closed end 42 of the hydraulic cylinder to adjust the retracted position of the cleaning head, and to insure that the lid seats against the lip with the desired seating force.

In the system shown in FIG. 2, the casing is mounted in the nozzle 43 and the hydraulic cylinder 40 is located outside of the vessel. This arrangement is generally preferable where a large enough opening is available because it minimizes the intrusion of the retracted cleaning system into the vessel. For example, when the system is the mounted in the top of a chemical reactor such as a polymerizer, the system shown in FIG. 2 allows the maximum liquid level in the reactor. However, the system shown in FIG. 2 generally requires approximately a fourteen inch opening in the reactor. FIG. 4 illustrates a system which only requires approximately a 6 inch opening, and thus may be more suitable for existing vessels without large openings. In this system the hydraulic cylinder extends through the nozzle 83 in thevessel wall, and the casing is supported by the hydraulic cylinder.

As in FIG. 2, the casing 90 of the system in FIG. 4 is closed by a lid 91 pivotally attached to pins 93 mounted on a frame 94 attached to the rotating housing 87 of the cleaning head. The pins are also parallel to the plane of the lip 92 on the casing, and are located on the opposite side of the rotating housing from the nozzles 83.

In this embodiment, the lid 91 is closed by a rod 95 supported in guides 96 attached to frame 94. The rod extends generally parallel to the supply tubes axis between a cam surface 97 on the lid and an annular surface 98 at the top of the casing 90. The annular surface 98 is parallel to the plane of the lip 92 on the casing, which, as in the system in FIG. 2, is at right angles to the supply tubes axis.

A coil spring 101 surrounds and extends beyond the end of the rod 95 nearest to the annular surface 98. As the cleaning head 86 moves into the casing 90, spring 101 contacts the annular surface 98 and moves the rod 95 longitudinally with respect to the rotating housing 87. The other end of the rod 95 presses against the cam surface 97 on the lid, thereby pivoting the lid 91 into the closed position. As may be seen in phantom in FIG. 4, the lid is pivoted into the closed position, that is, it is pivoted substantially parallel to the lip 92, before the cleaning head 86 has moved all the way into the casing 90. A stop is provided on frame 94 in order to prevent the spring 101 and the closing rod 95 from pivoting the lid past the point where it is substantially parallel to the plane of the lip.

A second coil spring 102 surrounds the closing rod 95 and biases the rod towards the annular surface 98. This spring insures that the closing rod 95 will not stick in the guides and prevent the lid 91 from opening as the cleaning head moves out of the casing. Preferably, the second coil spring 102 has a much lower spring factor than coil spring 101, that is, less force is required to compress it. Thus, the first coil spring 101 can easily overpower the second spring 102 and close the lid as the cleaning head moves into the casing.

Since the lid 92 is pivoted into the closed position before it reaches the casing 90, it does not slide across the lip 92 of the casing. This reduces wear on the lid and lip. However, since the system shown in FIGS. 2 and 3 uses fewer moving parts, the possibilities of corrosion and/or fouling are reduced. Thus, the preference for one system as opposed to the other may vary from installation to installation. However, in most cases, either system will effectively protect the cleaning head from the environment inside the vessel. Either system may be used with the hydraulic system shown in FIG. I, the hydraulic system shown in FIG. 2, or a variety of other hydraulic systems to provide a simple, effective way for operating the system from outside the vessel and for flooding the closed chamber with fluid. Of course, it should be understood that those skilled in the art may make various modifications to the illustrated embodiments within the scope of this invention, which is de fined by the following claims.

We claim:

1. Apparatus for supplying cleaning fluid to and positioning a spray cleaning head within a vessel comprising:

a hydraulic cylinder having an open end and a closed end;

a cleaning fluid supply tube extending through the open end of the cylinder and adapted for reciprocation within the cylinder, said cleaning head being supported by and reciprocating with the fluid supply tube;

an annular piston on the tube, said cylinder, tube and piston defining an expansible chamber within the cylinder;

a pump for supplying cleaning fluid to the closed end of the cylinder, whereby the cleaning fluid exerts pressure on the annular piston; and

means for supplying fluid to-and draining fluid from the expansible chamber, whereby the pressure exerted by the cleaning fluid on the piston moves the supply tube and cleaning head from a retracted position to an extended position when fluid is drained from the expansible chamber, and the supply tube and cleaning head are moved back to the retracted position when fluid is supplied to the expansible chamber.

2. Apparatus according to claim 1 wherein the means for supplying fluid to and draining fluid from the expansible chamber comprises a multi-way valve adapted to connect the expansible chamber to the discharge of said pump or to a drain line.

3. Apparatus according to claim 1 wherein:

the means for supplying fluid to the expansible chamber comprises a second pump; and

a pressure relief valve connects the discharge of the second pump to the closed end of the hydraulic cylinder.

4. Apparatus according to claim 1 further comprising: A

an open ended casing attached to the hydraulic cylinder and surrounding the supply tube, whereby reciprocating the supply tube moves the cleaning head into and out of the casing; and

a lid adapted to close the end of the casing when the cleaning head is in the casing, whereby the cleaning head is protected from materials inside the vessel.

5. Apparatus according to claim 4 further comprising means for filling the casingwith fluid when the lid is closed.

6. Apparatus according to claim 5 wherein the means for filling the casing comprises the cleaning fluid supply P P- 7. Apparatus according to claim 5 wherein:

the means for supplying fluid to the expansible chamber comprises a second pump; and

the means for filling the casing with fluid comprises a pressure relief valve connecting the discharge of said second pump to the closed end of the hydraulic cylinder.

8. In a vessel cleaning system including a cleaning fluid supply tube adapted for reciprocation along its axis and a spray cleaning head mounted on and reciprocating with the supply tube, said cleaning head having a housing adapted for rotation about the supply tubes axis and nozzles rotatably attached to the housing, an enclosure for the cleaning head comprising:

an open ended casing surrounding the supply tube,

whereby reciprocating the supply tube moves the cleaning head into and out of the casing;

a lid attached to the rotating housing;

means for pivoting the lid out of the spray pattern of the nozzles as the cleaning head moves out of the casing; and

means for pivoting the lid to close the open end of the casing as the cleaning head moves into the casing.

9. Apparatus according to claim 8 wherein:

the lid seats against an annular lip on the open end of the casing, said lip lying in a plane at right angles to the supply tubes axis; and

the lid pivots about an axis parallel to the plane of the lip.

10. Apparatus according to claim 8 wherein the nozzles are attached to one side of the rotating housing and the lid is pivotally attached to the other side of the rotating housing.

11. Apparatus according to claim 8 wherein:

the supply tubes axis is generally vertical; and

the lid is pivotally attached to the rotating housing at a location offset from the lids center of gravity, whereby the means for pivoting the lid out of the spray pattern comprises the weight of the lid.

12. Apparatus according to claim 8 wherein:

the lid seats against an annular lip on the open end of the casing;

the lip is generally coaxial with the supply tube, and

the means for pivoting the lidto close the open end of the casing comprises a member extending from one side of the lidand adapted to contact the lip as the cleaning head moves into the casing.

13. Apparatus according to claim 8 wherein the lid engages an annular lip on the open end of the casing and the means for pivoting the lid to close the open end of the casing comprises:

an annular surface within the casing parallel to the plane in which the lip lies;

a cam surface on the lid;

a rod extending generally parallel to the supply tubes axis between said cam surface and said annular surface, said rod being supported by the rotating housing and adapted for longitudinal movement with respect to the housing; and

a coil spring surrounding the end of the rod nearest to the annular surface and extending beyond the end of the rod, said spring being adapted to contact the annular surface as the cleaning head moves into the casing, whereby the rod moves towards the lid and the lid is pivoted to close the open end of the casing.

14. Apparatus according to claim 13 further comprising a second coil spring surrounding said rod and biasing the rod towards the annular surface, said second spring having a lower spring factor than the spring that contacts the annular surface.

15. Apparatus according to claim 13 wherein said rod and said coil spring are adapted to pivot said lid into a position generally parallel to said lip before the cleaning head has moved all the way into the casing.

16. Apparatus according to claim 8 wherein the easing is attached to a hydraulic cylinder adapted to reciprocate the supply tube and thereby move the cleaning head into and out of the casing:

17. Apparatus according to claim 16 wherein the casing is mounted in an opening in a vessel and the hydraulic positioner is located outside the vessel.

18. Apparatus according to claim 16 wherein the hydraulic cylinder extends through an opening in a vessel and supports the casing inside the vessel.

19. A vessel cleaning system comprising:

a hydraulic cylinder having a reciprocating cleaning fluid supply tube extending therefrom;

a cleaning head mounted on the end of the supply tube, said cleaning head having a housing adapted for rotation about the longitudinal axis of the supply tube and nozzles rotatably attached to one side of the housing;

an open ended cylindrical casing attached to the hydraulic cylinder and extending coaxial with and surrounding the supply tube, whereby reciprocating the supply tube moves the cleaning head into and out of the casing;

an annular lip on the open end of the casing, said lip lying in a plane at right angles to the axis of the supply tube;

a lid pivotally attached to the opposite side of said rotating housing from the nozzles;

means for pivoting the lid out of the spray pattern of the nozzles as the cleaning head moves out of the casing; and

means for pivoting the lid to seat against the lip on the casing as the cleaning head moves into the easmg.

20. Apparatus according to claim 19 wherein:

the supply tubes axis is generally vertical; and

the lid is attached to the rotating housing at a location offset from the lids center of gravity, whereby the means for pivoting the lid out of the spray pattern comprises the weight of the lid.

21. Apparatus according to claim 19 wherein the means for pivoting the lid to seat against the lip comprises a memberextending from one side of the lid and adapted to contact the lip as the cleaning head moves into the casing.

22. Apparatus according to claim 19 wherein there is an annular surface within. the casing parallel to the plane of the lip and the means for pivoting the lid to seat against the lip comprises:

a cam surface on the lid;

a rod extending generally parallel to the supply tubes axis between said cam surface and said annular surface, said rod being mounted in guides attached to the rotating housing and adapted for longitudinal movement with respect to the housing; and

a coil spring surrounding the end of the rod nearest to the annular surface and extending beyond the end of the rod, said spring being adapted to contact the annular surface as the cleaning head is moved into the casing whereby the rod is moved towards the lid and the lid is pivoted parallel to the plane of the lip.

23. Apparatus according to claim 22 wherein said coil spring is adapted to contact the annular surface and pivot the lid parallel to the lip before the cleaning head has moved all the way into the casing. 

1. Apparatus for supplying cleaning fluid to and positioning a spray cleaning head within a vessel comprising: a hydraulic cylinder having an open end and a closed end; a cleaning fluid supply tube extending through the open end of the cylinder and adapted for reciprocation within the cylinder, said cleaning head being supported by and reciprocating with the fluid supply tube; an annular piston on the tube, said cylinder, tube and piston defining an expansible chamber within the cylinder; a pump for supplying cleaning fluid to the closed end of the cylinder, whereby the cleaning fluid exerts pressure on the annular piston; and means for supplying fluid to and draining fluid from the expansible chamber, whereby the pressure exerted by the cleaning fluid on the piston moves the supply tube and cleaning head from a retracted position to an extended position when fluid is drained from the expansible chamber, and the supply tube and cleaning head are moved back to the retracted position when fluid is supplied to the expansible chamber.
 2. Apparatus according to claim 1 wherein the means for supplying fluid to and draining fluid from the expansible chamber comprises a multi-way valve adapted to connect the expansible chamber to the discharge of said pump or to a drain line.
 3. Apparatus according to claim 1 wherein: the means for supplying fluid to the expansible chamber comprises a second pump; and a pressure relief valve connects the discharge of the second pump to the closed end of the hydraulic cylinder.
 4. Apparatus according to claim 1 further comprising: an open ended casing attached to the hydraulic cylinder and surrounding the supply tube, whereby reciprocating the supply tube moves the cleaning head into and out of the casing; and a lid adapted to close the end of the casing when the cleaning head is in the casing, whereby the cleaning head is protected from materials inside the vessel.
 5. Apparatus according to claim 4 further comprising means for filling the casing with fluid when the lid is closed.
 6. Apparatus according to claim 5 wherein the means for filling the casing comprises the cleaning fluid supply pump.
 7. Apparatus according to claim 5 wherein: the means for supplying fluid to the expansible chamber comprises a second pump; and the means for filling the casing with fluid comprises a pressure relief valve connecting the discharge of said second pump to the closed end of the hydraulic cylinder.
 8. In a vessel cleaning system including a cleaning fluid supply tube adapted for reciprocation along its axis and a spray cleaning head mounted on and reciprocating with the supply tube, said cleaning head having a housing adapted for rotation about the supply tube''s axis and nozzles rotatably attached to the housing, an enclosure for the cleaning head comprising: an open ended casing surrounding the supply tube, whereby reciprocating the supply tube moves the cleaning head into and out of the casing; a lid attached to the rotating housing; means for pivoting the lid out of the spray pattern of the nozzles as the cleaning head moves out of the casing; and means for pivoting the lid to close the open end of the casing as the cleaning head moves into the casing.
 9. Apparatus according to claim 8 wherein: the lid seats against an annular lip on the open end of the casing, said lip lying in a plane at right angles to the supply tube''s axis; and the lid pivots about an axis parallel to the plane of the lip.
 10. Apparatus according to claim 8 wherein the nozzles are attached to one side of the rotating housing and the lid is pivotally attached to the other side of the Rotating housing.
 11. Apparatus according to claim 8 wherein: the supply tube''s axis is generally vertical; and the lid is pivotally attached to the rotating housing at a location offset from the lid''s center of gravity, whereby the means for pivoting the lid out of the spray pattern comprises the weight of the lid.
 12. Apparatus according to claim 8 wherein: the lid seats against an annular lip on the open end of the casing; the lip is generally coaxial with the supply tube, and the means for pivoting the lid to close the open end of the casing comprises a member extending from one side of the lid and adapted to contact the lip as the cleaning head moves into the casing.
 13. Apparatus according to claim 8 wherein the lid engages an annular lip on the open end of the casing and the means for pivoting the lid to close the open end of the casing comprises: an annular surface within the casing parallel to the plane in which the lip lies; a cam surface on the lid; a rod extending generally parallel to the supply tube''s axis between said cam surface and said annular surface, said rod being supported by the rotating housing and adapted for longitudinal movement with respect to the housing; and a coil spring surrounding the end of the rod nearest to the annular surface and extending beyond the end of the rod, said spring being adapted to contact the annular surface as the cleaning head moves into the casing, whereby the rod moves towards the lid and the lid is pivoted to close the open end of the casing.
 14. Apparatus according to claim 13 further comprising a second coil spring surrounding said rod and biasing the rod towards the annular surface, said second spring having a lower spring factor than the spring that contacts the annular surface.
 15. Apparatus according to claim 13 wherein said rod and said coil spring are adapted to pivot said lid into a position generally parallel to said lip before the cleaning head has moved all the way into the casing.
 16. Apparatus according to claim 8 wherein the casing is attached to a hydraulic cylinder adapted to reciprocate the supply tube and thereby move the cleaning head into and out of the casing.
 17. Apparatus according to claim 16 wherein the casing is mounted in an opening in a vessel and the hydraulic positioner is located outside the vessel.
 18. Apparatus according to claim 16 wherein the hydraulic cylinder extends through an opening in a vessel and supports the casing inside the vessel.
 19. A vessel cleaning system comprising: a hydraulic cylinder having a reciprocating cleaning fluid supply tube extending therefrom; a cleaning head mounted on the end of the supply tube, said cleaning head having a housing adapted for rotation about the longitudinal axis of the supply tube and nozzles rotatably attached to one side of the housing; an open ended cylindrical casing attached to the hydraulic cylinder and extending coaxial with and surrounding the supply tube, whereby reciprocating the supply tube moves the cleaning head into and out of the casing; an annular lip on the open end of the casing, said lip lying in a plane at right angles to the axis of the supply tube; a lid pivotally attached to the opposite side of said rotating housing from the nozzles; means for pivoting the lid out of the spray pattern of the nozzles as the cleaning head moves out of the casing; and means for pivoting the lid to seat against the lip on the casing as the cleaning head moves into the casing.
 20. Apparatus according to claim 19 wherein: the supply tube''s axis is generally vertical; and the lid is attached to the rotating housing at a location offset from the lid''s center of gravity, whereby the means for pivoting the lid out of the spray pattern comprises the weight of the lid.
 21. Apparatus according to claim 19 wherein the means for pivoting the lid to seat against the lip comprises a member extending from one side of The lid and adapted to contact the lip as the cleaning head moves into the casing.
 22. Apparatus according to claim 19 wherein there is an annular surface within the casing parallel to the plane of the lip and the means for pivoting the lid to seat against the lip comprises: a cam surface on the lid; a rod extending generally parallel to the supply tube''s axis between said cam surface and said annular surface, said rod being mounted in guides attached to the rotating housing and adapted for longitudinal movement with respect to the housing; and a coil spring surrounding the end of the rod nearest to the annular surface and extending beyond the end of the rod, said spring being adapted to contact the annular surface as the cleaning head is moved into the casing whereby the rod is moved towards the lid and the lid is pivoted parallel to the plane of the lip.
 23. Apparatus according to claim 22 wherein said coil spring is adapted to contact the annular surface and pivot the lid parallel to the lip before the cleaning head has moved all the way into the casing. 